The present invention relates to a tightening fixture for a chuck. More particularly, the present invention relates to a built-in torque readout device for measuring the torque applied to tighten the lock nut of a chuck.
In high speed tooling, it is important to tighten the lock nut of a chuck to a specified torque. If the lock nut is not tightened sufficiently, the tool may come loose during operation posing a hazardous threat to anyone standing nearby. On the other hand, over-tightening may cause damage to the tool or chuck.
Tightening fixtures are currently in use to assist tightening of a lock nut on a chuck. Generally speaking, a tightening fixture comprises a stationary block having an opening formed therein to receive a toolholder or chuck. Typically, the toolholder will include a flange having one or more keyways. Keys fixed to the stationary block engage the keyways on the toolholder to prevent rotation of the toolholder, relative to the tightening fixture. Thus, the tightening fixture functions in a manner similar to a vice or clamp to hold the toolholder in a fixed position as the lock nut is tightened.
Currently, there are no tightening fixtures which have the capability of measuring the tightening torque applied to tighten the lock nut on a chuck. Torque is determined by using a conventional torque wrench to tighten the lock nut. However, a torque wrench may not always be available when it is needed. Further, torque wrenches cannot be used in all applications.